Manufacture of phosphorus, etc.



v No Drawing;

Patented cc. 2, l924.

RICHARD o. TOLMAN, or wasnmeron, msrnrcr or columns.

MANUFACTURE OF PHOSPHORUS, ETC.

To all whom it may concern."

Be it known that I, Rrorrxnn C. @FOLMAN, a citizen of the United States, residin at Washington, in they District of Colum ia,

have invented a new and usefullmprove ment in the Manufacture of Phosphorus,

Etc, of which the following is a specification. I

I am aware that in the production of the alloy commercially termed ferro-phos (a description'and analysis of ferro-phos can be found inUnited States Letters Patent No; 1,265,076, page 2, lines 30, 4A, 58and 75) it has been customary to furnace either in an electric furnace or a blast furnace a charge consisting of sand, coke and phosphate rock with which is incorporated a relatively large quantity of iron ore or metallic iron, and the' final product produced is the aforesaid ferro-phos for which at the present time there is a relatively limited market. In the production of such a product a not inconsiderable quantity of phosphoric acidmay escape in the waste gases, particularly in case an electric furnace is used where the temperatures are so high as to drive phosphorus out of its combination with iron, or in blast furnace operation in cases where the proportion of iron ore added to the burden is reduced below that usual for the production of ferro-phos, and efforts have been made to recover this phosphoric acid. It is also lmown in carrying out such a furnace operation for the production of phosphorus vapors, that the addition of a metal or a metal ore, 1 n particular iron or iron ore, greatly fac1l1- tates the process by maintaining a molten bath whichserves to keep up the temperature of the refractory slag or in other ways not-yet thoroughly understoodto facilitate the escape of the ph osphorus vapors. My invention 1s based on the fact that phosphorus compounds of metals, part cularly ferro-phos itself, which 1s a compound or mixture of compounds corres onding to the formula Fe P will, if adciied to the charge in lieu of iron or other metal or metal ore, serve'in an essentially similar manner which Application filed January is, 1921. Serial'No. 437,641.

to promote the escape of phosphorus va ors, an this product may be recovered an repeatedly used in the production of further quantities of phosphoric acid or hosphorus.

In carrying out my improv process 1 preferablyproceed as follows:

A charge consisting of seventy parts phos-" phate rock, thirty-five parts of sand, ninety .parts of coke and about twenty parts by weight of ferro-phos, is introduced in-to a furnace of any suitable type, for example, a

blast furnace or an electric furnace.

In producin phosphoric acid the charge is heated in a b ast furnace to a temperature of 1500 C. for a period of one hour until a substantially all of the available phosphorus has been vaporized and such vapors are con ducted to a suitable stove to complete the conversion of the hosphorus into phosphoric anhydride if desired electrical precipitation of the phosphorus comounds may be resorted to in order more efectly to recover the same. Y

When producing elemental hosphorus the oxidation of the volatilized p osphorus is of course dispensed with and the issuing gases are maintained underreducing conditions.

By my process it is possible to make available substantially the entire phosphorus content of the ore since it is not necessary that a substantial portion" of the same shall be converted into ferro-phos as is customary, at the gresent time, as the ferro-phos agent employ in proportions of about 10% to 12% for example: can be recovered with but a very small amount of loss and utilized in connection with the furnacing of further charges.

The ferro-phos isseparated and recovered by removing it in a molten form through a suitable tap'hole at the bottom of the furnace as is customary in the operation of.

1. The process which consists in incor- 1 porating in a charge of non-metallic phosphatic material and carbonaceous reducing material a relatively small portion of material consisting of a metallic compound of phosphorus having the catalytic properties of ferro-phos furnacing the charge at a suflioient temperature to effect the volatilization of a quantity of phosphorus-corresponding substantially to that represented by the phosphorus content of the said phosphatic material, recovering the metallic compound .of phosphorus fromthe charge and successively ire-utilizing the same for the treatporating in a charge of phosphate mineral and carbonaceous reducing material a catalytic agent comprising essentially an iron compound of phosphorus having the catalytic properties of ferro-phos, furnacing the charge at a sufiicient temperature to eil'ect the volatilization of the greater portion'of the phosphorus represented by the phosphorus content of such mineral, recovering the catalytic agent and utilizing the same in a fresh charge of phosphate mineral and carbonaceous reducing material, and repeating such treatment upon such fresh charge.

3. In the process of recovering phosphorus and phosphorus compounds from nonmetallic nhosphatic material, the step which consists in adding a metallic phosphorus compound having the catalytic properties of ferro-phos to a charge of non-metallic phosphatic material and a carbonaceous reducin material.

4. iii the process of recovering phosphorus and phosphorus compounds from phosphate mineral, the step which consists in furnacin rock, car onaceous reducing material and a relatively small portion of an iron compound of phosphorus having the catalytic properties offerro-phos to a suflicient temperature to effect volatilization of the phosphorus content of such phosphate mineral.

5. lihe process of recovering phosphorus and phosphorus compounds from phosphate mineral, the step which consists in reducing phosphate mineral in the presence of carbonaceous reducing material and a catalytic agent consisting essentially of a phosphorus compound of iron having the catalytic properties of terro-phos, said catalytic agent being prwent essentially throughout the entire period of treatment.

6. The process of recovering. phosphorus and phosphorus compounds from phosphate mineral consisting in reducing phosphate mineral in the presencaof a catalytic agent consisting essentially of a phosphorus compound of iron having the catalytic properties of ferrohos.

Signed at ashington, D. 0., this tenth day of May, 1920.

RIGHARD C. TOLMAN.

a charge consisting of phosphate 

